The MSILOG indeed showed that the setup was looking for the RTM language files in the original location where the setup files were, but they are long gone… with the RTM DVD no where to be-found (RTM trial files + the oldest Language Pack bundle are in a non compatible version) this situation was doomed to failure.

So, I’ve turned to manually remove any references to the Client / Server language packs on the server, this included removing a whole bunch of registry keys:

And it works ! Now, I guess that with a script this would have been much quicker then the registry method, but at least now I’m (and you are) aware of this workaround , and here’s the script for your usage:

** edit the $setuplocation variable for your directory of the servicepack.